Apparatus for continuously extruding net-like structures composed of twisted multifilament yarns

ABSTRACT

APPARATUS FOR MAKING NET-LIKE STRUCTURES IN WHICH EXTRUDED GROUPS OF STREAMS OF STRAND-FORMING MATERIAL ARE SET INTO GROUPS OF FILAMENTS, WITH THE INDIVIDUAL GROUPS OF FILAMENTS BEING TWISTED INTO YARNS AND INTERLACED AND/ OR TWISTED WITH EACH OTHER CONCOMITANTLY WITH THEIR FORMATION.

Oct. 19, 1971 T. H. FAIRBANKS 3,613,161

APPARATUS FOR CONTINUOUSLY EXTRUDING NET-LIKE STRUCTURES COMPOSED OFTWISTED MULTIFILAMENT YARNS Filed May 16, 1969 2 SheetsSheet 1 Oct. 19,1971 T. H. FAIRBANKS 3,513,161

APPARATUS FOR CONTINUOUSLY EXTRUDING NET*LIKE STRUCTURES COMPOSED OFTWISTED MULTIFILAMENT YARNS UnitedStates Patent O1 ice 3,613,161Patented Oct. 19, 1971 3,613,161 APPARATUS FOR CONTINUOUSLY EXTRUDINGNET-LIKE STRUCTURES COMPOSED OF TWIST- ED MULTIFILAMENT YARNS TheodoreH. Fairbanks, West Chester, Pa., assignor to FMC Corporation,Philadelphia, Pa. Filed May 16, 1969, Ser. No. 825,213 Int. Cl. B29t 3/06' U.S. Cl. 18--12 N Claims ABSTRACT OF THE DISCLOSURE Apparatus formaking net-like structures in which extruded groups of streams ofstrand-forming material are set into groups of filaments, with theindividual groups of filaments being twisted into yarns and interlacedand/ or twisted with each other concomitantly with their formation.

The present invention is directed to an apparatus for making, byextrusion, net-like structures of twisted multifilament yarns.

In U.S. Pat. No. 3,331,903, there is disclosed a method and apparatusfor making a net from plastic material by extruding a plurality of pairsof monofilaments of plastic material in such a manner that the filamentsin each pair are spaced from each other in a first direction and thepairs of filaments are spaced from each other a given distance in asecond direction. The monofilaments of each pair of filaments arerevolved, at the moment of their extrusion and before being solidified,about an axis extending between the filaments of each pair of filamentsso as to twist the filaments of each pair together and to thusintegrally connect the filaments. One of the filaments of each pair offilaments is then moved in a second direction a distance equal to thespacing between pairs of filaments while continuing the extrusion of thefilaments, afterwhich pairs of filaments are again revolved asheretofore described. By continuously repeating the above steps andsetting of the extruded filaments of plastic material, a netlikestructure is provided.

In my United States patent application entitled Method for ContinuouslyExtruding Net-Like Structures, Ser. No. 825,210, filed May 16, 1969there is disclosed a method of making net-like structures of woven orbraided monofilaments using an apparatus similar to that described inU.S. Pat. No. 3,331,903.

Using conventional knitting, weaving or knotting processes, the strengthand flexibility characteristics of net-like structures can be broughtinto a desired balance using preformed twisted multifilament yarn. Onthe other hand, extruded net-like structures formed of monofilaments, asproduced by methods disclosed in U.S. Pat. No. 3,331,903 and myabove-noted pending application, as well as other methods known in theart, generally exhibit either good strength and poor flexibility or poorstrength and good flexibility. Accordingly, a primary object of thisinvention is the provision of an improved and more satisfactoryapparatus for making net-like structures by extrusion.

Another object of this invention is to provide an apparatus for makingextruded net-like structures which possess good strength and flexibilitycharacteristics.

Still another object is the provision of an apparatus for making, byextrusion, continuous net-like structures of twisted multifilamentyarns.

A further object is the provision of an apparatus for making, byextrusion, net-like structures having twisted multifilament yarns whichare interlaced with each other and/ or twisted together at theircrossing points.

These and other objects are accomplished in accordance with the presentinvention by an apparatus in which a plurality of separate groups ofclosely spaced streams of flowable strand-forming material arecontinuously extruded, with the groups arranged in pairs. The groups ofstreams of each such pair of groups are spaced from each other in afirst direction and the pairs of groups of streams are spaced from eachother a given distance in a second direction. At least the surfaces ofthe extruded streams are set to provide groups of filaments, after whichthe filaments of each individual group are twisted to provide yarns. Thegroups of streams of each such pair of groups are revolved about an axisextending between the groups of each respective pair of groups to atleast exchange the positions thereof. Relative movement is then impartedto the groups of streams in each such pair of groups in the seconddirection to arrange at least certain of the groups of each such pair ofgroups into different pairs. By continuously repeating the abovesequence of movements concomitantly with the continuous extrusion of thegroups of streams of strand-forming material, setting of such streamsinto groups of filaments and twisting of the individual groups offilaments into yarns, a net-like structure of interlaced or twistedyarns is provided.

Preferably, the streams in each group of streams are alike in number,size and spacing, the groups of streams in each of the pairs of suchgroups are spaced like distances in the first direction and the pairs ofgroups are spaced like distances in the second direction.

During the revolving of the groups of streams of each such pair ofgroups, they are moved through an angle equal to a multiple of Morespecifically, the groups of streams of each such pair of groups may berevolved through an angle of only 180, providing that the direction ofrelative movement of the groups of streams in the second direction andthe direction of revolution of the groups of each pair of groups is eachreversed after the respective alternative movement has been completed,That is, relative movement of the groups of streams in each pair of suchgroups in a second direction is eifected alternately with revolving ofthe groups of each pair of groups. Thus, if the direction of relativemovement of the groups is reversed after each revolution of the groupsof each such pair of groups, and the direction of revolution of thegroups of each pair of groups is reversed after each relative movementof the groups, then each revolution of the groups may be limited to only180. With this procedure the twisted multifilament yarns are interlacedwith each other so that the resulting net-like structure is of woven orbraided construction.

Revolving the groups of streams of each such pair of groups through anangle of 360 or further multiple of 180 will cause the individualtwisted multifilament yarns formed from the respective groups of streamsto be twisted with each other at their points or locations of crossing.The resulting net-like structure will exhibit good strength, yet will beflexible in view of the absence of bonding between the filaments in theindividual yarns and between the yarns which are twisted to each other.

Obviously, the groups of streams of each such pair of groups may berevolved only 180 in certain instances and 360 or further multiples of180 in other instances so that the resulting net-like structure willexhibit interlaced and twisted junctions between the multifilamentyarns.

If it is intended to revolve the groups of streams of each such pair ofgroups through an angle of 360 or further multiple of 360, the pairs ofgroups of streams, and the filaments and yarns formed therefrom, may bearranged in a circular array.

Relatively moving the groups of streams of each such pair of groups inthe second direction may be achieved by moving only one group of streamsof each pair of groups or by moving both groups of each pair of groupsoppositely of each other or in the same direction but at different ratesof speed. Further, when in a circular array, the groups of streams ofeach such pair of groups may be moved relative to each other byoscillating or rotating the one or both of such groups about an axiscommon to all the pairs of groups,

More particularly, the apparatus of the present invention includescylindrical extrusion nozzles which are arranged as a plurality ofspaced pairs to which fiowable strand-forming material is continuouslydelivered under pressure. Each of the nozzles has a multiplicity ofextrusion orifices whereby the flowable strand-forming materialdelivered to each nozzle is extruded therefrom as a group of separatestreams. The extruded streams of each individual group are rapidly setinto filaments and the nozzles are continuously rotated to twist eachgroup of filaments into a yarn.

Periodically, each pair of nozzles is revolved through an angle equal toa multiple of 180 about an axis located between the respective nozzlesof each such pair of nozzles whereby the groups of streams issuing fromsuch pair of nozzles at least exchange positions. Operative alternatelywith the nozzle revolving means are means for relatively moving nozzlesof each pair of nozzles into positions as to be arranged in differentpairs.

The revolving means of the apparatus includes a plurality ofsemi-circular tables, with each having an opening within which isrotatably mounted an individual nozzle. The apparatus may be equipped torevolve the tables which support each pair of nozzles through an angleof only 180", with the direction of revolution of such tables beingreversed after each relative movement of the nozzles of such pairs ofnozzles and the direction of relative movement of the nozzles also beingreversed after each revolution of the nozzles of each such pairs ofnozzles. The pairs of nozzles may be arranged in a circular array inwhich instance the apparatus would be adapted to revolve each pair ofnozzles through 360 or further multiple of 360 As in conventionalextrusion apparatus for making netlike structures, suitable means, suchas nip rollers, are provided for continuously advancing the finishednet-like structure away from the extrusion apparatus concomitantly withits production.

The teachings of the present invention are applicable for use with avariety of materials, which are referred to by the terms plastic orstrand-forming materials, including materials which are thermoplastic,such as polyamides or superpolyamides, polyesters, polyvinyl chloride,copolymers thereof, polyolefins, cellulose acetates, etc., natural orsynthetic rubbers, thermosetting materials or wet-spinnable materials,such as viscose, cuproammonium cellulose, or carboxymethyl cellulose.Such materials may include various additives such as stabilizers, dyes,foaming agents, etc., if so desired. It will be apparent that the mannerby which the extruded streams are set will de pend upon the particularmaterial which is being employed.

For a greater understanding of this invention, reference is made to thefollowing detailed description and drawing in which FIG. 1 is a verticalsection taken longitudinally of the apparatus of the present invention;

FIG. 2 is a horizontal section taken substantially along the line II--IIof FIG. 1;

FIG. 3 is a partial vertical section, on an enlarged scale, takentransversely through the apparatus substantially along the line IIIIIIof FIG. 2;

FIG. 4 is a view of the bottom of the apparatus of the present inventionas viewed along the line IV-IV of FIG. 3;

FIG. 5 is a fragmentary section taken substantially along the line VV ofFIG. 3;

FIG. 6 is a section of a portion of the apparatus taken substantiallyalong the line VIVI of FIG. 3; and

FIG. 7 is a perspective view of one of the elements of the apparatus.

With reference to the drawing, the apparatus includes a pair of verticalsupport members 15 and 17, side walls 19 and 21, which terminate wellabove the lowermost ends of the support members 15 and 17 and a top wall23. Walls 25 and 27 project from each of the opposing sides of the walls19 and 21 and together define channels 29 within wihch are slidablyreceived elongated plates 31 and 33. Openings 35 and 37 are provided inthe support members 15 and 17 for the passage of the plates 31 and 33therethrough. The plates 31 and 33, together with the support members 15and 17, side Walls 19 and 21 and top wall 23, define a chamber 39.

Flowable strand-forming material is continuously delivered underpressure into the chamber 39 through a conduit 41 from a suitablesource, not shown. Gaskets are provided in the area of the openings 35and 37 in the support members 15 and 17 to prevent leakage ofstrandforming material during sliding movement of plates 31 and 33. Atank 43 is provided for containing a suitable setting liquid 45 in thearea below the plates 31 and 33.

In the specific embodiment illustrated, the contacting opposinglongitudinal edges 47 and 49 of the plates 31 and 33 lie in a commonplane and are each formed with a series of like, equally spaced,semi-circular recesses 51 and 53, respectively. Tables 55 and 57, havingportions which correspond in shape to recesses 51 and 53, are positionedwithin respective of such recesses for movement relative thereto, ashereafter described. The tables 55 and 57 are of like construction and,as best shown in FIG. 7, each include a straight or fiat surface or wall59, a semi-circular wall 61 and a top flange 63 which projects over andrests on the top surface of the respective plates 31 and 33. Gear teeth65 are formed along the walls 61 of the respective tables 55 and 57 at alocation as to be exposed below the bottom surfaces of the plates 31 and33.

Each of the tables 55 and 57 is formed with a suitable opening 67 withinwhich is rotatably mounted a nozzle 69 having a flange 71 at one end anda plurality of openings 73 at its opposite end. The nozzle flanges 71are seated within recesses extending annularly about the openings 67 inthe respective tables 55 and 57, as shown in FIG. 3. Each of the nozzles69 is formed with teeth 75 along its outer periphery, by means of whichthe nozzles are continuously rotated as hereafter described in detail.

With the flat surfaces '59 of the tables 55 and '57 aligned with eachother and with the opposing longitudinal edges 47 and 49 of the plates31 and 33, at least one of the plates 31 and 33, and the tables 5 5 and57 carried thereby, is moved or shifted longitudinally. Preferably, bothof the plates 31 and 33 are shifted longitudinally in oppositedirections relative to each other. This relative longitudinal movementof the plates 31 and 33 is effected through pins 77 and 79 which projectfrom the respective plates 31 and 33 and ride along grooves 81 and 83formed in opposing surfaces of cams 85 and 87.

The earns 85 and 87 are of like construction and are fixed, inout-of-phase relationship, to a shaft 89 which is supported by bearings,such as shown at 91, and is intermittently driven by suitable means, notshown. As more fully described hereafter, the plates 31 and 33 arepreferably moved a distance substantially equal to one-half of thecenter-to-center spacing of the respective recesses '51 and 53 so as tomove the tables 55 and 5-7, which are carried by the plates 31 and 33,into diiferent positions of alignment with each other.

Alternately with the longitudinal sliding movement of the plates 31 and33, aligned tables 55 and 57 which are carried by such plates aretogether revolved as a unit through an angle of 180 or further multiplethereof so as to at least exchange the positions of such pair of alignedtables. If in the practice of the method the tables are revolved throughan angle of only 180, each such revolving movement is in a directionopposite to the previous revolving movement thereof so as to provide forinterlacing of yarns, as more fully described hereafter.

Revolving of the tables is effected by gear racks 93 and 95, which meshwith the gear teeth 65 formed along the semi-circular walls 61 of suchtables 55 and 57. The racks 93 and 95 are themselves intermittentlydriven by gears 97 and 99, respectively, which are fixed to shafts 101and 103. The racks 93 and 95 are guided for straight line motion bychannels 105 which are formed by rabbeting the projecting walls 25, asshown in FIG. 3.

In the arrangement illustrated in the drawing, the racks 93 and '95 aredesigned to revolve aligned tables 55 and '57 through an angle of only180, alternately with the shifting of the plates 31 and 33, and thusgear teeth are present only along selected lengths of the racks 93 and95 are omitted from portions indicated at 107 and 109. To provide formovement of the racks 93 and 95 a distance necessary for revolvingaligned tables 55 and 57 through an angle of only 180, the gears 97 and99 may be in the form of segment gears which are intermittently drivenby oscillating the shafts 101 and 103 in opposite directions.

Fixed to and depending from each of the plates 31 and 33 are a pair ofangle members 111 each having a vertical flange 113 and a horizontalflange 115. As best seen in FIGS. 5 and 6, the vertical flanges 113 ofthe angle members 111 are each formed with rigid support hangers 117which extend through spaced elongated slots 119 in the walls 25 and aresecured by screws 121 to the respective plates 31 and 33. By thisarrangement, the angle members !111 will both travel with the plates 31and 33 during their reciprocating movements.

Elongated platforms 123 are dovetailed to the horizontal flanges 115 ofthe angle members 111 for sliding movement generally perpendicular tothe common plane, as defined by the abutting longitudinal edges of theplates 31 and 33. As shown in FIG. 4, each of the platforms 123 isformed with a series of arms 125 which project toward the abovementionedcommon plane. A sprocket 127, carried by a shaft 129, is rotatablymounted to the free end of each of the arms 12 5. Laced about thesprockets 127 carried by the respective platforms 123 is an endlesschain 131 which is adapted to engage with the teeth 75 projecting fromthe periphery of the nozzles 69. The endless chains 131 are continuouslydriven through gears 133-, each of which is fixed to one of the shafts129 carried by each of the platforms 123. The gears 133 mesh with andare driven by gears 135 which are fixed to the output shafts of separateelectric motors 137.

The motors 137 serve to advance adjacent reaches of the pair of endlesschains 131 in opposite directions so that the nozzles 69 arecontinuously rotated in the same direction. To insure continuousengagement of the endless chains 131 with the nozzle teeth 75,notwithstanding the movement of the nozzles as their supporting tables5-5 and 57 are revolved, the platforms 123- are resiliently urged towardsuch nozzles by a series of leaf springs 139 located between therespective platforms and the adjacent flanges 113 of the angle members111.

In the practice of the method with the apparatus of the presentinvention described above, flowable strand-form ing material isdelivered under pressure through the conduit 41 and into the chamber 39.With the elements of the apparatus positioned as shown in FIG. 2, theflowable strand-forming material issues from the orifices 73 of thenozzles 69 as a group of straight streams, which are rapidly set intofilaments, as by the liquid 45.

The motors 137 are then placed and maintained in continuous operation todrive the endless chains 131. The adjacent reaches of the pair ofendless chains 131 are driven in opposite directions and are maintainedengaged with the teeth 75 on the nozzle peripheries by the actionexerted upon the platforms 123 by the leaf springs 139. Thus, themovement of the endless chains 131 serves to continuously rotate thenozzles 69 so that the group of streams issuing from the orifices of therespective nozzles 69, and preferably the filaments formed from suchstreams, are twisted into yarns.

The cams 8-5 and 87 are now operated to shift the plates 31 and 33 inopposite directions, preferably a distance equal to one-half of thecenter-to-center spacing of the plate recesses 51 and 53. During thismovement, the angle members 111 travel with the respective plates 31 and33, as heretofore explained.

With different tables 55 and 5-7 now aligned with each other, plates 31and 33 are held stationary while the racks 93 and 95 are shifted by thegears 97 and 99 to revolve only aligned pairs of tables 55 and 57through an angle of only 180. The nozzles 69 which are mounted withinand moved with such tables are continuously rotated by the endlesschains 131 so that the twisted yarns formed from the streams ofstrand-forming material issuing therefrom are moved from one side of thecommon plane to the other thereof.

The plates 31 and 33 are now shifted by the earns and 87 to the samedegree but in opposite directions to their prior movement to aligndifferent tables 55 and 57 with each other. Again with the plates 31 and33 held fixed, the racks 93 and are driven to revolve only alignedtables 55 and 57 through an angle of only The direction of revolution ofthe tables 55 and 57, howver, is in a direction opposite to that inwhich aligned tables were previously revolved. By continuously repeatingthe above-described steps, a net-like structure results having twistedmultifilament yarns which are interlaced with each other.

As heretofore mentioned, in lieu of revolving the aligned tables 55 and57 through an angle of only 180, the tables may be turned through 360 ora further multiple of 180 to provide a net-like structure in whichindividual extruded twisted multifilament yarns are themselves twistedWith other of such yarns at their crossing points. Moreover, if themovement of the tables '55 and 57 is limited to complete 360 turns, orfurther multiples thereof, the various elements of the apparatus may bearranged in a circular array to thereby produce tubular net-likestructures in which the twisted yarns are twisted with other yarns attheir points of crossing.

I claim:

1. Apparatus for making net-like structures including cylindricalextrusion nozzles arranged as a plurality of spaced pairs, means fordelivering flowable strand-forming material to said nozzles, amultiplicity of orifices in each of the nozzles whereby strand-formingmaterial is extruded therefrom as a group of separate streams, means forsetting the extruded streams of strand-forming material into filaments,means for rotating the nozzles of each pair of nozzles whereby thefilaments formed by the individual nozzles are twisted into yarns, meansfor periodically revolving each pair of nozzles through an angle equalto a multiple of 180 about an axis located between the respectivenozzles of each such pair of nozzles, and means operative alternatelywith said revolving means for relatively moving nozzles of each pair ofnozzles into positions as to be arranged in different pairs.

2. Apparatus as defined in claim 1 wherein said revolving means includesa plurality of semi-circular tables which are disposed with their flatsides in abutting relationship, and an opening in each of said tablesfor ro-, tatably supporting therein an extrusion nozzle.

3. Apparatus as defined in claim 1 wherein said means for relativelymoving said nozzles includes means for reciprocating the nozzles of eachpair of nozzles in 180 out-of-phase relationship and wherein saidrevolving means moves the pairs of nozzles through an angle of only 180in opposite directions alternately with each stroke of saidreciprocating means.

4. Apparatus as defined in claim 1 wherein said revolving means movesthe pairs of nozzles through angles equal to a multiple of 360 5.Apparatus as defined in claim 7 wherein said nozzle rotating means turnseach of the nozzles continuously and with all of said nozzles moving inthe same direction.

References Cited UNITED STATES PATENTS 2,919,467 1/1960 Mercer l813 X Q3,331,903 7/1967 Mine 1812 X N J. SPENCER OVERHOLSER, Primary ExaminerL. R. FRYE, Assistant Examiner US. Cl. X.R.

1813 N; 26417, Dig. 81

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,613,161Dated October 19, 1971 Inventor(s) Theodore H. Fairbanks It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Col. 2, line 42, "alternative" should read --alternate. Col. 3, line 47,"pairs" should read -pair Col. 4, line 21, "wi'hch" should read which-.Col. 5, line 28, after "95" insert and-. Col. 7, line 14, "7" shouldread l Signed and sealed this 4th day of April 1972.

(SEAL) Attest:

EDWARD M.PLETCHER,-'JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents RM P0 10 0! 0 69) USCOMM-DC 60376-P89 UYS. GOVERNMENTPRINTING OFFICE I965 0-3ii-S3

